


In Love With a Killer

by RavenBird



Category: Shadowhunters (TV)
Genre: Alec Lightwood Deserves Nice Things, Alec Lightwood Is So Done, Alternate Universe - Serial Killers, BDSM, Bottom Alec Lightwood, Double Life, Enemies to Lovers, Knifeplay, Lies, M/M, Magnus Bane is a Little Shit, Murder, Past Rape/Non-con, Plot Twists, Police Officer Alec Lightwood, Rope Bondage, Serial Killers, Serial Killers Magnus Bane, Top Magnus Bane, Twisted, Vigilante Magnus Bane
Language: English
Status: Completed
Published: 2019-03-11
Updated: 2019-05-11
Packaged: 2019-11-15 14:59:17
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 2,466
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18075596
Author URL: https://archiveofourown.org/users/RavenBird/pseuds/RavenBird
Summary: Magnus Bane is a serial killer that has never been caught.It's surprising as he always leaves secret clues for the hot officer chasing him.Alec is an NYC Police Officer and a darn good one. His track record is almost perfect.Almost.The one case he can't crack are the murders by the impossible "Warlock Killer"But that's about to change, because, finally, Alec knows where Warlock is.Comments appreciated





	1. Chapter 1

**Author's Note:**

> From Archive of Our Own (AO3) Writers - Prompts
> 
> "If you want me" the hero panted "come and get me" 
> 
> The villain paused, languidly sweeping a hand up and under their chin. "Want you in which way, darling? Don't get me wrong, both involve ropes, but it's an important distinction to make before we proceed."
> 
> This got twisted really quick, read the tags, you have been warned.

No

No, not again. He was not getting away again!

The words raced through Alec's head as he chased after the criminal. The killer. The killer he'd been chasing for months.

The murders by "Warlock" were famous in New York and the one infuriating blip on Officer Alec Lightwoods perfect track record. 

The serial killer had appeared at the start of the year, his first kill being a 35 year old man named Toby Lucks, a convicted rapist released 3 years ago. They found him shirtless tied to a chair with his throat slit in his own home. It was labelled as murder in the first degree and left at that. Until it happened again less then a month later, the same crime, different person. Another ex rapist. It happened another two times before the Police used the term serial killer and Alec was made head of the case with the job of bringing the murderer in. 

It was the most frustrating case Alec had ever been assigned. They had no suspects, the killer left no evidence behind, no DNA from the scene of the crime and even more infuriating and a bit concerning. The killer had started leaving notes addressed just for Alec. Teasing little notes with an erotic undercurrent and signing off with some cryptic clue. 

"Better luck next time, Officer Lightwood.  
I'm sure you'll tie me down soon but until then I'll do it with somebody else.  
Try 10:30PM  
Warlock"

Alec had no idea how to interpret the notes. Was the guy trying to mess with him, flirt with him, give himself or all of them at once. It just made the case that much more interesting and confusing and Alec could admit he'd become obsessed with Warlock. It didn't help that the majority of the public liked the guy, calling him a vigilante. Serving proper justice to the awful men attacking woman on the street of New York. Some even thought the criminal was a woman. Alec could almost agree, rapist deserved life in prison but he didn't agree with killing. 

But the killing was about to stop. Alec had finally put the notes together and they weren't hinting at the next murder. They were instructions. 

10:30PM. Friday. 15th. June. Overland. Warehouse. Back Door.

To say Alec had gone over board would be an understatement, he had a squad team of 20 as well as multiple cars surrounding the overland Warehouse and a warrant to put the entire building on lock down that night. Not that it mattered.

Alec knew as he chased his target through the warehouse, a maze of boxes piled as high as the ceiling, that he was being deliberately lead. He'd long since been separated from his team who were occupied with boobie traps in another room but he didn't care. He had to catch the killer, he had to see this man, know who he was. Alec had to stop him. 

Suddenly he hit a dead end. How, he was sure he'd been right behind the killer. He spun on the spot trying to see where the man gone, had he climbed the boxes? Impossible. Behind him he heard chuckling but when he turned around there was nothing. He heard it again, a low rich laugh that promised mischief. 

"If you want me" Alec panted "come and get me" 

"Want you in which way, darling? Don't get me wrong, both involve ropes, but it's an important distinction to make before we proceed."

Oh

Oh no

Alec felt his heart stop because he knew that voice. The charming smooth voice that Alec had heard a hundred times before. The voice that made the hair on the back of his neck stand up and his back shiver. This just got complicated.

"Magnus" 

"Hey babe, miss me"

Magnus, beautiful, sexy, magical Magnus. The man Alec had been seeing for a year, his Dom. He was the killer. He was Warlock...Warlock had been Magnus's stage name at the BDSM club they'd met at. Alec wanted to hit himself, how could he have over looked that. All this time Magnus had been right in front of him, teasing him about his obsession with Warlock. How had he missed it. Magnus was wearing his trademark skinny jeans with chains, combat boots, a dark red open shirt and tight leather jacket. As well as jewellery and dark makeup that Alec usually loved and a shit eating grin. Alec backed up.

"What are you doing here" 

"I'm waiting for the handsome police officer to handcuff me. You didn't answer my question, Darling"

Alec stammered as he listened to Magnus speak, that low drawl that had Alec wanting to fall to his knees. He looked down and saw a knife strapped to Magnus belt. The knife he used during their scenes, the knife that had pretended to cut his throat countless times had actually slit someone else's throat. The thought was terrifying and arousing. Alec stepped back again, this was so fucked up.

"You think I'd let you tie me up after what you've done"

"You have done before. Just last week you were tied to my bed. You enjoyed yourself if memory serves" 

Alec clenches his jaw to keep the moan caught in his throat in. It had been such a good night. He had felt so good, Magnus made him feel so good. 

"I didn't know. I didn't know you were Insane"

"Pretty sure I warned you about that the night we met"

Alec remembered that night as well. It was his first time in that type of club. He'd finally plucked up the courage to get what he wanted and Magnus been the one to open the door. He'd been beautiful and dangerous looking that night. Telling him that he'd take Alec apart piece by piece. Magnus was circling him now, like predator stalking his prey. It wasn't the first time Alec had felt like this with Magnus. This time was electric. 

He was backed against the wall. He could escape, he has his gun strapped to his hip and he has handcuffs. He could end this, all he had to do was let Magnus get a little closer but he couldn't move. Couldn't even think of arresting Magnus. 

"Why?" 

"How about I tell you over drinks" 

In the distance Alec could he hear his squad team, they were in the same room as them, looking for him. Magnus heard them too.

"Last chance darling. There coming so I must be going. Are you joining me" 

He whispered it right in Alec's ear, letting his breathe ghost down his neck and Alec gave in. He'd regret it, he knew that but he was so gone for this man. 

Alec nodded.

Magnus flashed him a smile like knives and then everything went black.


	2. Chapter 2

Alec woke up groggily, his neck ached and he had a banging head ache. He was in a dimly lit room, making it harder to find his bearings. A gentle breeze flowed through the room, it was cold on his chest. 

Alec’s brain came back online then, he was shirtless. Shirtless and tied to a chair with ropes. Well fuck. 

“Sleeping beauty finally awake”

Alec turned to the voice, Magnus was reclined back in his own chair, minus the ropes. 

“Did you sleep well?” Magnus tried again looking at Alec with amused eyes.

“What did you do to me, how’d I get here?” Alec asked, only vaguely remembering their conversation from the warehouse.

“I smashed your head against the wall the I carried you here. Don’t worry, I’ve sorted out the head wound.” How, how could he say that so simply? Like it was normal, and Magnus had carried him here. Alec was a full head taller than Magnus. Magnus snorted.

“I’m going to try not to be offended by your surprise darling”

“Don’t call me that” Alec snapped.

“Why ever not?” Magnus asked, genuinely confused. 

“Because your going to kill me” Magnus arched his brow at him and Alec, as best he could, gestured to the chair he was in. Magnus smiled brightly then. 

“Oh this, this is just for show. Set the mood while we have our drinks” Magnus got up then, choosing to instead sit on the table directly in front of Alec where two wine glasses were sitting. 

“Did you have drinks with your other victims?” Alec fished.

“Your not a victim and no I didn’t. I gave them quick deaths, which was more than thy deserved.” Magnus’s voice dropped low and angry and Alec became keenly aware of the knife still strapped to his side. Alec had been relieved of his own weapons. 

“So it was because they were rapists?” Magnus did look mildly offended now. 

“Of course, I don’t kill without reason” Alec cocked his head to they side.

“You make it sound like you’ve killed before?” 

“I have, a long time ago. If you hadn’t already noticed Alexander, I’m a bit of a psychopath. I enjoy other people’s pain, it relaxes me” Alec gasps, Magnus’s eyes are so dark when he talks, slow and steady, every word measured and thought out. He chuckles briefly. It almost sounds sad. 

“However, unlike most, I’m aware it’s wrong. It’s why I started doing BDSM, I could carry out my “urges” without seriously hurting anyone, the aftercare process was perfect for coming down from the high.”

“So why start killing again?” Alec asked.

“Because I finally had the chance to take my revenge for my sister” what, just what, where did Alec go with that. Thankfully Magnus continued.

“8 years ago, she and 3 other woman were gang raped and inadvertently killed by a group of 10 men. They were only given 5 years in jail and then released. Now their all back for a, lads reunion. I decided to crash the party” 

Everything locked into place, Magnus was killing off his sisters attackers one by one until they were all dead. In his head Alec quickly did the math.

“There’s been 9 killings so far, you said there was 10 men so...”

“I have one more to go, yes” 

“And then you’ll stop” Alec asked hopefully. It shouldn’t matter, Magnus had already committed 9 murders he should be going to jail, Alec should be planing to escape so he could get back to the station. But he wasn’t thinking that. Not at all. 

“Yes, then I stop, I promise” his voice sounded sincere, more like the Magnus Alec had come to know and love this past year. 

There it was, love. Alec loved Magnus. It was why he was actually considering letting Magnus get away with this. Let him kill the last man, it wasn’t like the guy was innocent anyway. They wouldn’t find any evidence, like always and the Warlock case would be left unsolved. Things could continue like they were. He was shocked with himself, he wanted a relationship with a psychopath. It was wrong, it was so wrong.

“Untie me” Magnus laughed.

“We’re not done talking love” he sat down in Alec’s lap, arms thrown carelessly around his neck. His weight felt nice. 

“Am I safe with you?” Alec just managed to keep his words steady. “Am I safe with you when we do a scene together, am I safe with you when we just hang out, are my friends and family safe when I introduce you?” Magnus took a second to respond, clearly surprised by Alec’s sudden questions.

“Yes, I’d never you or anyone innocent for that matter” he said solemnly. Alec nodded, a smile just touching his lips.

“I believe you, I trust you so trust me too and untie me” Magnus hesitated before pulling his knife free and cutting the ropes loose, they fell away with a heavy thud. 

Alec slowly reached for the knife, pulling it from Magnus’s hand gently and dropped it next to the chair too. He ran his hands up the others arms while Magnus stared him like he was a wonder. Something he’d never seen before. Eventually, Alec’s hands rested on both of Magnus’s cheeks, framing his beautiful face and kisser him.

It was nothing like their other kisses, they were biting, rough and dominating. This one was soft, gentle, almost hesitant. But Alec felt the tension bleed out of the both of them when their lips touched. He sighed as he pulled away, looking deep into the others eyes.

“Swear it, swear this is the last one and that you’ll tell me if you ever want to do this again” Alec begs gripping on to Magnus like he’s gonna run.

“I swear on my sisters memory, I’ll stop after this last kill and I’ll tell you if this ever happens again.”

“Ok then” they kiss again, this one hungrier than the last. Alec almost missed Magnus pulling out a needle. He looks at the other man as if to say really. Magnus grins.

“You’ve been missing for a day love, can’t have you seen leaving here, it be shame to be caught so close to the end and I wouldn’t want you incriminated with me” Magnus has a good point. He sighs.

“Fine, I hate needles”

“I’ll keep that in mind” Magnus teases and his pushes the plunger down. Alec feels it’s effect immediately, eyes dropping. 

“Sweet Dreams Alexander”

****

Alec had woken up in a rental car later that day, not far from his apartment. He’d gone back to work claiming that Warlock a mask and that the criminal had drugged him and left him in a car overnight. It wasn’t untrue. The officers were curious as to why Alec hadn’t been killed but Alec brushed them off saying the killer obviously liked playing games. 

It was scary how easy it was to deceive the police, Alec was starting to get How Magnus had gotten away with what he was doing. 

A month later it happened. Robert Smith, 35 years old, ex rapist released from jail 3 years ago. Alec was surprised no one had noticed all the victims had been jailed for the same crime. He was surprised he hadn’t noticed it. 

Like always there was no evidence left at the crime scene, no note either. Alec almost missed it. It was dubbed another Warlock kill and Alec didn’t get home till late once again because of the paper work.

But when he did get home, Magnus was waiting for him, lounging on his couch like owned the place and satisfied grin on his face. 

“How do you feel?” Magnus’s grin widened, making him look like the Cheshire Cat. 

“Like I want to celebrate” he said in his silky voice pulling Alec towards the bedroom. 

And Alec saw the freshly washed knife on his kitchen counter, he didn’t comment on it.

**Notes for the Chapter:**

> So this got a lot darker than I meant for but I like it. 
> 
> I’m aware that Magnus should probably be in hospital and not in a BDSM relationship but hey they’ll be fine. 
> 
> Hope you enjoyed. Sorry for any mistakes


End file.
